Painted panels were prepared in a wide range of gloss and in three achromatic colors (white, middle grey, and black) by varying the composition and heat treatment of an automotive acrylic‐lacquer system. Magnitude scaling was used to estimate visual dissimilarities between the members of all possible pairs of specimens in series of 15–20 samples. The data were analyzed by multidimensional scaling using several commercially available computer programs. The experiments were carried out and the results are discussed for evaluation of several types of gloss: distinctness‐of‐image, specular, contrast, sheen, and reflection haze. The resulting interval scales were all unidimensional. The visual data were correlated with a variety of instrumental gloss measurements made on the same specimens by using commercially available glossmeters.

A number of equations are suggested for estimating intrinsic viscosity from one measurement of relative viscosity at a convenient concentration. Experimental data illustrate the validity of the equations.

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The U.S. Army has undertaken a program to develop an instrumental method for assessing the acceptability of textiles for color difference from a standard. This article reports the results of the first phase of the program, an assessment of three commercial color‐measuring instruments (Diano Match‐Scan, Hunter D‐54P‐5, Macbeth MS‐2000) for objective textile acceptability judgment. It is concluded that the three instruments are essentially equivalent in the precision and accuracy of the measurement of color and color difference using a wide variety of samples, at least over periods of up to seven weeks. All measures of repeatability lead to the conclusion that the uncertainties involved are well below the just‐perceptible color difference. Levels of absolute accuracy achieved depend greatly on the details of operation, data treatment, and calibration, but are considered satisfactory for each of the instruments tested. With respect to certain other parameters, the performance of the instruments is less satisfactory. Rejection of the specular component differs significantly among the three, as does the selection of weights for tristimuus calculations. One instrument, as tested, exhibited significant sensitivity to weave orientation in textile samples. Finally, we find that the distributions of tristimulus values obtained with each of the instruments show large deviations from normality, severely limiting the significance of conventional statistical treatment of such data.

Between 1981 and 1983, a working Group of USTC‐1.3 of the CIE prepared new recommendations giving for the first time detailed instructions for the calculation of CIE tristimulus values, for inclusion in Publication CIE No. 15.2, a revision of the CIE document on colorimetry first published in 1971. The new recommendations state that the standard method of performing the integration forming the basic definition of tristimulus values shall be by summation at a wavelength interval of 1 nm over the wavelength ranCe 360–830 nm, but that for most colorimetric purposes the approximation of summation at a 5‐nm interval over the range 380–780 nm should suffice. Recognizing that measured data fulfilling these requirements are not usually available, recommendations were also made concerning abridgement, interpolation, extrapolation, truncation, and the calculation of weighting factors. Although tables of weighting factors were not included in the recommendations to the CIE, they have since been calculated in cooperation with the Working Group and published by the ASTM. This article describes the recommendations, now accepted by the CIE and providing clear and complete guidelines for the uniform calculation of CIE tristimulus values.

Possible pitfalls and errors in the measurement of haze by ASTM Method D 1003 are pointed out and discussed. This propert?, is an important measure of the optical clarity of plastic $films and sheets. Although special hazemeters are usually used for the measurement, it is demonstrated that accurate haze measurements can be performed by using widely available integrating-sphere spectrophotometers. Additional advantages of obtaining both spectrophotometric and goniophotometric data for the characterization and interpretation of haze are pointed out.

The heat of sublimation of linear paraffin chains from the crystalline form to the gas at OaK is calculated from heats of fusion, heats of vaporization, and heat capacities of solid, liquid, and gaseous hydrocarbons. The heat of sublimation, which is defined as the lattice energy of the crystalline phase of linear polyethylene, is 1.84 kcal/mole of CH2 groups. The heat of fusion of crystalline linear polyethylene is 0.922 kcal/mole of CH2 groups.

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